1. Field of the Invention
The present invention relates to a strainer for filtering a flow stream of liquid or gas passing therethrough.
2. Description of the Related Art
A filtering strainer which retains larger pieces while permitting smaller pieces and liquids to pass therethrough has many applications. In particular, a strainer can be utilized in the oil and gas industries where it is installed upstream of rotating equipment such as gas compressors or pumps to protect the internal components from being damaged due to carried over solid objects.
The use of a strainer for straining a fluid flow is well known. One example of a strainer is disclosed in U.S. Pat. No. 4,839,038 to McLain, II which relates to a fluid strainer and flow corrector for use with a fluid flow measurement device such as a turbine-type flow meter.
Another example of a strainer is illustrated in U.S. Pat. No. 5,500,115 to Nehm, et al.
Conventional strainers are known for generating pressure pulsation in association with vortex shedding and/or eddies due to the stream flow of liquid or gas passing through them. In some cases, the pressure pulsation could coincide with a system's natural frequencies and cause serious damage to the system. In other cases, the pressure pulsation may cause piping vibrations, damage rotating equipment internals, and result in associated high level noise as well as high pressure drop. For instance, vibrations created by the vortices can cause cracks in the strainer mounting parts.
One of the previous approaches was to remove the strainer, which is not acceptable because it will leave internal components such as a compressor without protection against foreign objects. Another approach was to relocate the strainer, which is not practical and did not solve the root case nor resolve the noise issue. Yet another approach was to change the angle of inclination for the strainer, which fails to prevent the pressure pulsation problem. Some other designs of strainers purporting to reduce vibration are flawed by their inherent design. Due to these necessary constraints, they could not be manufactured with a large enough size to be usable in many industries, making those solutions not viable.
Thus, a strainer is needed that can filter a flow stream passing therethrough, while reducing vortex shedding and related noise and vibrations. Such strainer would solve the root cause and not be sensitive to location of the strainer in piping machinery.